Spring structures in MicroElectroMechanical systems (MEMS) have become increasingly important in a wide variety of applications. These applications include electronic packaging, test and measurement probing, integrated high quality factor inductors, electrical interconnects, fluid distribution and printing applications.
Traditional methods of forming small spring structures have disadvantages. Often the fabrication process used to produce these springs produce sharp angled bends or “kinks” in the spring at or near the point where the spring lifts up from the substrate such as is shown in FIG. 6. When the angled bend is oriented in a direction that opposes the spring flex the angled bend serves as a weak point that is prone to failure with repeated use.
Alternate fabrication techniques exist to avoid such bends. However, these alternative techniques use precisely controlled timing of etch rates. Etch rates depend on many parameters such as etchant concentrations, the exact composition and thickness of the layer being etched, and the spring geometry. Consistently reproducing the multiple parameters is difficult in a commercial production environment.
Thus a method for forming spring structures that does not rely on timing to control etching and results in spring structures that do not form angled bends that are susceptible to breakage is needed.